A wireless device may be configured to carry out a channel sensing procedure before accessing a channel. The channel sensing may be based on measuring the channel and comparing measurement results with a threshold. If the channel is determined, on the basis of the comparison, to be idle or to contain transmissions that allow simultaneous channel access, the wireless device may access the channel and carry out a frame transmission. Otherwise, the wireless device may refrain from the channel access. Setting the threshold may be important in terms of spectral efficiency and/or interference control.